Simple network management protocol (SNMP) is a UDP-based network protocol. It is used mostly in network management systems to monitor network-attached devices for conditions that warrant administrative attention. SNMP is a component of the Internet Protocol Suite as defined by the Internet Engineering Task Force (IETF). It consists of a set of standards for network management, including an application layer protocol, a database schema, and a set of data objects. SNMP exposes management data in the form of variables on the managed systems, which describe the system configuration. These variables can then be queried (and sometimes set) by managing application.
In typical SNMP use, one or more administrative computers called managers have the task of monitoring or managing a group of hosts or devices within a network. Each managed device runs, at all times, a module called an agent which reports information via SNMP to the manager. Specifically, the information is reported via SNMP protocol data units (PDUs). Among these PDUs, a trap is a type of PDU used to report an alert or other asynchronous event about a managed device.
When the SNMP is deployed on a gateway, the trap notification can be used report, e.g. cold boot, warm boot, managed Ethernet switch change, linkup, linkdown, etc.
However, when deploying the SNMP on the gateway, it's found that the gateway sometimes cannot correctly distinguish between cold boot and warm boot.